For decades, numerous suspension systems have been employed for enhancing shock absorption during application of the wheel as a caster for carts, stands, gurneys, wagons, bins, tubs, and other vehicles both powered and without power. Usually these types of suspension systems relate to the use of some form of springs, coil springs, leaf springs, and which provide normally for absorption of shock in the vertical direction. But, where a caster is utilized, in particular rugged conditions and usage, the terrain encountered may present forces that are generated in other than the vertical direction, and could be even horizontally exerted, or angularly exerted, in addition to impact and shock that is encountered along the vertical dimension. These types of suspension systems, for cushioning the ride of any vehicle, are well documented.
The current invention is designed to provide for a suspension system that can absorb shock, more efficiently, that is exerted from the vertical and other angular directions.
Initially, as early as 1908, inventors addressed how to suspend a wheel internally with springs in various configurations, generally radially, to cushion the wheels against road impacts in early automobiles and casters.
Pertinent suspended wheels can be seen beginning with the patent to Dunn, U.S. Pat. No. 927,511. This spring wheel shows springs located around rods that bias the rod outwards. However, the '511 patent lacks a slot on the interior of the wheel rim and has no threads in the hub that engage the rods. The rods and springs are also covered by a disc of some sort against road debris.
The patent to Graff, U.S. Pat. No. 895,554 shows a vehicle wheel having telescoping spokes. A spring is outside each spoke and the outer portion of the spoke rests upon the spring and has a Y shaped yoke. The inner portion of the spoke acts as a tube and receives the outer portion. The inner portion threadily connects to the hub. Unlike this patent, the present invention has a single piece spoke that engages a slot in the interior of a wheel rim.
Then the patent to Dye, U.S. Pat. No. 1,176,705, shows another spring wheel. This spring wheel has a series of radial spokes formed from two slideably connected parts within a spring. The spring is contained within a nut and a flange. In this patent, the spoke is pinned to the hub and to the rim and has two portions. The present invention on the other hand is threaded to the hub and moves partially along the rim in a slot while the spokes are a single piece.
Other related patents include U.S. Pat. No. 929,570 to Driefer on a spring wheel, U.S. Pat. No. 1,043,075 to Day on a resilient wheel, U.S. Pat. No. 1,077,388 to Bray on a vehicle wheel, U.S. Pat. No. 1,146,314 to Dugger on a vehicle wheel, U.S. Pat. No. 1,245,184 to Bropson on a resilient wheel, U.S. Pat. No.1,284,415 to Million on a spring wheel, U.S. Pat. No. 1,463,064 to Sequeira on a resilient wheel, U.S. Pat. No. 1,510,414 to Patterson on a spring wheel, U.S. Pat. No. 1,613,084 to Casey on a resilient wheel, U.S. Pat. No. 1,978,312 to Kanai on a motorcycle frame, and U.S. Pat. No. 3,194,293 to Kindley on a shock absorbing caster wheel.
Then around 1951 and later, a spiral type of suspension spring was utilized upon at least the rear wheel of a motorcycle, to absorb better the forces of impact, particularly in off road racing and competition.
Related types of suspensions that have been patented can be seen in the patent to Kimball, U.S. Pat. No. 95,039. This particular device shows a spring wheel that has a variety of semi-radially disposed spokes, each of which has a spring bias rod and tube combination, and which surrounds the hub, for suspending the rim and its tire in place.
The patent to Gray, U.S. Pat. No. 1,086,162, shows another spring wheel where the spokes essentially include spring mounted rod and tube combinations, in order to further buffer and provide shock absorbing for the supported wheel.
The patent to Ubezzi, U.S. Pat. No. 1,144,879, shows another vehicle wheel, similar to the Gray device, wherein the spokes essentially have spring mounts within them, to enhance shock absorbing.
The patent to Jutila, U.S. Pat. No. 1,155,246, shows another resilient wheel. This device incorporates tangential springs, inner poles between spokes and the rim, apparently for providing cushioning with respect to the rim. The steel wires of the wheel are fixed, in the manner of spokes, between the rim brackets and the inner rim ring, as can be noted.
The patent to Cruthers, U.S. Pat. No. 1,306,951, shows a yieldable bearing and support therefor. This is more of a bearing but incorporates an inner hub, with the outer rim, and does include lateral cushioning springs within its structure. These are biased against the rocker arms. Thus, lateral support is provided through this type of structure, for a wheel like structure, but unlike the current invention.
The patent to Shafer, U.S. Pat. No. 1,343,986, shows another resilient wheel that includes spokes, identified as helical springs upon the elements as shown, but these connect directly between the hub, and the outer rim.
The patent to Weirich, U.S. Pat. No. 1,436,840, is upon another vehicle wheel. This device apparently pivotally connects its arms to the outer rim or tread member of the wheel, and does include a series of shock absorbing devices therebetween.
It appears that there may be a direct connection between the hub and the rim, through some type of linkage on the shown arms.
The patent to Yankauer, U.S. Pat. No. 1,456,565, shows another resilient wheel. This wheel shows a structured hub that incorporates a series of members, having varying members extending therefrom, with tangential springs provided for mounting of the hub relative to its rim. This design differs from the structure of the present invention.
The patent to Vobach, U.S. Pat. No. 1,465,747, shows another spring wheel with another way of mounting through the use of a spring by a spoke between the hub and the rim of the tire.
The patent to Stoltz, U.S. Pat. No. 1,584,679, shows another resilient wheel. This one uses spokes arranged at right angles, and which are spring biased, to add to the support for the wheel, and to add to the absorption of shock.
The patent to Henap, U.S. Pat. No. 1,979,935, shows a hydraulic spoke wheel. This device includes a variety of hydraulic cylinders arranged as spokes at various angles to enhance the resiliency of mounting of the wheel upon its hub.
The patent to Molitor, U.S. Pat. No. 3,896,868, shows a resiliently mounted auxiliary wheel for a tractor. This wheel includes a variety of spring biased telescoping rods and tubes, as shock absorbers, functioning as spokes within the rim, for supporting the wheel.
Finally, the patent to Cornellier, U.S. Pat. No. 6,698,480, shows a non pneumatic tire and wheel system. This device simply utilizes compound shocks, as can be noted, in lieu of spokes within the solid tire which is not the structure of the present invention.
The present invention overcomes the limitations of the prior art explained above. That is, the art of the present invention allows a slotted rim for relocating a suspension system temporarily within a wheel under a non vertical force or shock. The slotted rim is on the interior face of the rim and connects with the suspension system supporting the hub generally at the center of the caster.